Pneumatic tires used for on-road and off-road driving have a problem such that trapping of stones (stone stuffing) in circumferential main grooves needs to be reduced. When such trapping of stones occurs, separation may appear on a tread by stone drilling, and a retread rate may decrease, bringing about unfavorable results. For this reason, to reduce such trapping of stones, a recent heavy duty pneumatic tire is provided with a protrusion (stone ejector) on a groove bottom of the circumferential main groove.
A technology disclosed in Patent Document 1 has been known as a conventional pneumatic tire that employs such configuration. According to the conventional pneumatic tire (a pneumatic tire that includes a stone-stuffing protective protrusion), a stone-stuffing protective protrusion projects continuously along the circumferential direction from the groove bottom of the circumferential main groove on the tread of the pneumatic tire, and the stone-stuffing protective protrusion includes an outer surface on which curvilinear concaves and convexes are alternately formed in waves in the circumferential direction.    Patent Document 1: Japanese Patent Application Laid-open No. H6-239107